SILICIOUS AND HORNY SPONGES WILSON. 365 



expanded cladomes. The anatriaenes are fairly abundant. The 

 rhabdome is several millimeters long, in a particular case 2.8 mm. ; 

 about 5 {x thick near the cladome, then becoming hair-like; clads 

 55-80 [jl long. 



The sigmas in the type have a length of 22 p. They are smaller, 

 only 10-12 \i long, in the Albatross specimen. They are abundant in 

 the dermal membrane and in the interior, especially in the canal 

 walls. 



Spheres were found in only one of Dendy's specimens (Dendy, 

 1905, p. 1)0). They are present in the Albatross specimen; scantily 

 scattered in the choanosome ; more common in the ectosome, but here 

 only abundant in the walls of some of the narrow canals. They are 

 spheroidal or slightly irregular, 2-8 pi in diameter ; sometimes packed 

 closely together in little groups of 2-4, occasionally looking as if they 

 were fusing. 



Owing to the smaller size of some of the spicules, especially the 

 sigmas and until the measurements are better known for more speci- 

 mens from different localities, the Albatross sponge might be pro- 

 visionally held apart from the type as a variety. 



T. hirsuta has been recorded from the Gulf of Manaar (Ceylon) 

 and the west coast of British India (Okhamandal in Kattiawar). 

 Two closely related forms are T. (Cinachyra) vodtzkowi Lenden- 

 feld, from Zanzibar (Lendenfeld, 1897), and T. cinachyroides Hent- 

 schel, from southwest Australia (Hentschel, 1911, p. 281). The latter 

 has a small variety of oxea which marks it off. The former seems to 

 differ from Dendy's species only in spicule measurements, and should 

 probably be merged into it. 



TETILLA (CINACHYRELLA) CLAVIGERA (Hentschel) 



Plate 39, fig. 4 

 Tethya claiiyera Hentschel, 1912, p. 327. 



Station D5169, one specimen. 



Hentschel had two fragments from the Aru Islands. These he 

 interpreted as belonging to a massive, spheroidal or hemi spheroidal 

 sponge. This inference is confirmed by the Albatross specimen which 

 is subspheroidal, 70~80 mm. in diameter, with no base or obvious 

 surface of attachment. 



The vestibular spaces or poriferous pits are scattered abundantly 

 and yet not thickly over the whole surface. They have the same 

 shape as in the type specimen, each being a radially elongated ellip- 

 soidal sac opening to the exterior by a narrower canal. They are 

 larger than in Hentschel's specimen, a typical pit measuring 11 mm. 

 in depth, with a bottom width of 5 mm. and a circular aperture 2 mm. 

 in diameter. Some of the apertures are surrounded by short, rather 

 vague, fringes of projecting spicules. Probably where the fringes 



